Carding

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Carding

  1. 1. Chapter 3The Card Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 1
  2. 2. The CardIt is always considered by the experts that card is the heart of the spinningmill.The statement “Well-carded is half-spun” demonstrate the immensesignificance of carding for the final result of the spinning operation.The importance of carding is still greater where new spinning systems areconcerned.The considerable influence of the card on yarn quality arises from the verycomplex series of events in the process itself and also from the pressureto adopt an extremely high production rate on economic grounds. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 2
  3. 3. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 3
  4. 4. Taker-in Flats Main cylinder Cleaning unit Doffer Detaching Apparatus Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 4
  5. 5. The Tasks of the CardI-Opening to Individual FibersWhereas the blowroom opens the raw material only to flocks, The card must open tothe stage of individual fibers. This is essential to enable the elimination of impuritiesand performance of the other operation to be achieved. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 5
  6. 6. The Tasks of the CardII-Elimination of ImpuritiesElimination of foreign matter occurs mainly in the region of the taker-in. Only asmall part of the contaminants is carried along with the flat stripping or falls out atother positions.The degree of cleaningachieved by the moderncard is very high, in therange of 80-95%. Thus, theover-all degree of cleaningachieved by the blowroomand the carding together isas high as 95-99%.But card sliver still contains0.05-0.3% foreign matternormally. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 6
  7. 7. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 7
  8. 8. The Tasks of the CardIII-Elimination of dustIn addition to free dust, which can bedirectly sucked away as in theblowroom, the card also removes alarge proportion of the microparticlesthat are bound to the fibers.Significant fiber/metal or fiber/fiberfriction is needed in order to loosensuch particles. Both are available atthe card in considerabe measure: thecard is a good dust-removing machine. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 8
  9. 9. The Tasks of the CardIV-Disentangling of NepsWhereas the number of neps increases from machine to machine in theblowroom, The card reduces the remaining number to a small fraction.It is often falsely assumed that neps are eliminated at the card; in fact, they aremostly opened out.Only a certain number of the neps leave the machine unopened via the flatstrippings. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 9
  10. 10. The Tasks of the CardIV-Disentangling of NepsAn improvement in the disentangling of neps is obtained by:• Closer spacing between the clothings;• Sharper clothing;• Optimal (not too low) speeds of the taker-in;• Low doffer speeds; and• Lower throughput. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 10
  11. 11. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 11
  12. 12. The Tasks of the CardV-Elimination of Short FibersShort fibers can only be eliminated if they are pressed into the clothing.Since that is not possible with metallic clothing only the flats can be consideredin this context. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 12
  13. 13. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 13
  14. 14. The Tasks of the CardV-Elimination of Short FibersThe ability to select short as opposed to long fibers is based on the fact that longfibers have more contact with the clothing of the main cylinder than the short fibers.Thus, longer fibers are continually caught and carried along by the main cylinder.Short fibers, on the other hand, offer less surface to the clothing of the maincylinder; they therefore stay caught in the flats’ clothing, press into it, and leave themachine in the flat strippings. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 14
  15. 15. The Tasks of the CardV-Elimination of Short FibersThe card eliminates 1-2% of flat strippings. Approximately half of thestrippings are made up of short fibers.The card therefore eliminates fewer than 1% of short fibers. In thestaple diagram, this is hardly noficeable - the inaccuracy of the staple-measurement procedure is greater than the change in value. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 15
  16. 16. The Tasks of the CardVI-Fiber blendingThe card hardly improves long-term blending, since the residence timeof the material in the machine is too short. However, it improvestransverse blending because, apart from the OE-spinner, the card isthe only machine to process individual fibers.In the formation of the web, and with the repeated rotation of the fiberson the main cylinder, an intimate fiber-with-fiber mixing is achieved. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 16
  17. 17. The Tasks of the CardVII-Fiber OrientationThe effect of parallelizing is often attributed to the card. This is not completelyjustified, since the fibers in the web are not parallel, although they do have, forthe first time, a longitudinal order.The parallel condition is achieved on main cylinder, but it disappears during theformation of the web between cylinder and doffer. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 17
  18. 18. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 18
  19. 19. The Tasks of the CardVIII-Sliver formationIn order to be able to deposit the fiber material, to transport it, and process itfurther, an appropriate intermediate product must be formed.This outputmaterial is called sliver.In extreme cases, card sliver has a hank from 3 ktex (new spinning processes)to 6 ktex. Generally, the hank lies between 4 and 5.5 ktex in the spinning mills. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 19
  20. 20. The Tasks of the CardAutolevelling systemIn order to be improve the quality of the sliver autolevelling system may beused The autolevelling system provides lower mass variation in sliver. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 20
  21. 21. Web formationSliverProf.Dr. A.Kirecci - TE 211 Yarn Man. I 21
  22. 22. Operation Principle of the cardIn modern installations, raw material is supplied via pipe ducting(1) into the feed chute (2) of the card. An evenly compressedweb of about 500-900 ktex (g/m) is formed in the chute. (video) 1 2 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 22
  23. 23. Operation Principle of the cardA transport roller (3) passes material to the feed arrangement(4). This consists of a feed roller and a feeder plate designed topush the sheet of fiber slowly into the operating range of thetaker-in (5) while maintaining optimal clamping (video). 3 5 4 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 23
  24. 24. Operation Principle of the cardThe portion of the sheet projecting from the feed roller must becombed through and opened to flocks by the taker-in. Theseflocks are passed over grid equipment (6) and transferred to themain cylinder (8). 8 8 6 7 6 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 24
  25. 25. Operation Principle of the cardIn moving past mote knives, grids, carding segments (6), etc., thematerial loses the greater part of its impurities. Suction ducts (7)carry away the waste. The flocks themselves are carried alongwith the main cylinder to the flats (10) and are opened up toindividual fibers between these two devices in the actual cardingprocess. 106 7 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 25
  26. 26. Operation Principle of the card The flats (10) consist of 80-116 individual carding bars combined into a band moving on an endless path. Some 30-46 of the flats are located in the carding position relative to the main cylinder; the rest are on the return run. During this return, a cleaning unit (11) strips fibers, neps, and foreign matter from the bars. 1011 11 10 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 26
  27. 27. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 27
  28. 28. Operation Principle of the cardFixed carding bars (9) and (12) are designed to assist theoperation of the card. The underside of the main cylinder isenclosed by grids or cover plates. 12 9 9 12 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 28
  29. 29. Operation Principle of the cardAfter the carding operation been completed, the main cylindercarries along the fibers that are loose and lie parallel withouthooks. However, in this condition, the fibers do not form atransportable intermediate product. An additional cylinder, thedoffer (14), is required for this purpose. The doffer combines thefibers into a web because of its substantially lower peripheralspeed relative to the main cylinder. 14 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 29
  30. 30. Operation Principle of the cardA stripping device (15) draws the web from the doffer. Aftercalendar rolls (16) have compressed the sliver to some extent,the coiler (18) deposits it in cans (17). The working rollers,cylinders, and flats are provided with a clothing that becomesworn during fiber-processing, and these parts must be regroundat regular intervals and even replaced from time to time (video). 18 18 15 15 17 17 16 16 Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 30
  31. 31. The Operating Regions of the CardFeed of MaterialIn modern spinning installations, the card is the first machine todeliver a cohesive intermediate product.The product is expected to be very even and as far as possible freeof faults.Irregularities in the sliver can be traced through into the yarn, atleast in the spinning of carded yarns; they diminish yarn quality. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 31
  32. 32. The Operating Regions ofthe CardThe feed to the card must be veryeven.It is a minor problem where lap feed isused since each lap checked foraccuracy of count.However, in Flock-feed system, thebatts in the individual feed chutes ofall cards must be equally thick, evenlydistributed and must be of equaldensity to achieve even feeding.Also finely opened is required inFlock-feed system due to greatermaterial throughput. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 32
  33. 33. The Operating Regions of the CardLap/Flock-feedingAdvantages of lap feeding :1. Ease in the maintenance of constant lap thickness,2. The blends can be allocated to individual machines, but in flock feeds only to machine groups.Disadvantages:1. Greater manual effort in transport and lap change;2. More clean waste and faults caused by lap-changing and by correcting of faulty changes;3. An additional burden on the taker-in because scutcher laps are heavily compressed. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 33
  34. 34. The Operating Regions of the CardThe Taker-inThis is a cast roller with a diameter usually around 250 mm. Asawtooth clothing is applied to it. Beneath the taker-in, there is anenclosure of grid elements or carding segments.The purpose of the taker-in is;1. to pluck finely opened flocks out of the feed batt,2. to lead them over the dirt-eliminating parts under the roller,3. to deliver them to the main cylinder. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 34
  35. 35. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 35
  36. 36. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 36
  37. 37. The Operating Regions of the Card a,b,c : Grid elements, 1- Feed plate, 2- Feed roller 3- Taker-in roller, 4- Main cylinder Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 37
  38. 38. The Operating Regions of the CardThe adjustments on taker-in are,1. the thickness of the batt;2. the degree of openness of the raw material in the feed stock;3. the degree of orientation of the fiber in the feed stock;4. the aggressiveness of the clothing;5. the distance between the devices;6. the rotational velocity of the taker-in; and7. the material throughput. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 38
  39. 39. The Operating Regions of the CardMain cylinderThe cylinder is usually manufactured from cast iron but is nowsometimes made of steel.Most cylinders have a diameter of 1280 - 1300 mm and rotate atspeeds between 250 and 500 (or up to 600) r/min.It is essential that the speed can be changed, i.e. exactly adapted tothe requirements according to the raw material, spinning processetc., because the cylinder speed has some influence on yarnquality. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 39
  40. 40. WEBCLEAN systemProf.Dr. A.Kirecci - TE 211 Yarn Man. I 40
  41. 41. The Operating Regions of the CardBeneath the cylinder, and fully enclosing it, is a grid made of sheetmetal provided with transverse slots. This is designed to removeimpurities and maintain constant air-flow conditions.Flats creates a large surface area by its clothing strips. Long fibershave more contact with the clothing of main cylinder than the shortfibers. Therefore the long fibers are carried along but the shortfibers’ edges are caught by the flat strippings and leave themachine. The elimination is carried out by filling the clothing and theflats then past by a cleaning device. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 41
  42. 42. The Operating Regions of the CardThe DofferThe cylinder is followed by the doffer, which is designed to take theindividual fibers from the cylinder and condense them to a web. Thedoffer is mostly formed as a cast-iron drum with a diameter of about600-707 mm. It is fitted with metallic clothing and runs at speeds ofabout 300 m/min. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 42
  43. 43. The Operating Regions of the CardThe Detaching ApparatusIn the last-mentioned system, either two counter-rotating belts carry theweb into the centre (a) or a circulating band carries the web to one side ofthe card (b).It is advantageous if these sliver formers can be so manipulated that websections can be taken out for checking of neps. (a) Prof.Dr. A.Kirecci - TE 211 Yarn Man. I (b) 43
  44. 44. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 44
  45. 45. The Operating Regions of the CardCrushing Rollers (Web Crushing)Between the detaching roller (1) and the transverse slivercondenser belt (3), some manufacturers include two smooth steelrollers (2) arranged one above the other.They can run without loading, in which case they serve simply asguide rollers, or they can be loaded with a pressure of about 15N/cm and are thus converted into crushing rollers. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 45
  46. 46. The Operating Regions of the CardCrushing Rollers (Web Crushing)Where cotton with a medium-to-high dirt content is being processed,additional cleaning can be carried out here by squashing the foreignparticles.The fragments fall away immediately afterwards or in the subsequentmachines. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 46
  47. 47. The Operating Regions of the CardCoiling into cansThe material should be coiled into cans for the transport purposes.This can be achieved automatically by having one spare free canready at anytime. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 47
  48. 48. The Operating Regions of the CardClothingOf all the individual components of the card, the clothing has thegreatest influence on quality and productivity.Mills now have to make a difficult choice between hundreds ofavailable clothing types, a choice of the utmost importance. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 48
  49. 49. Selection criteria are;1. type and design of card;2. rotational speed of the cylinder;3. production rate;4. material throughput;5. raw-material type (natural or synthetic fibers);6. fiber characteristics (mainly fineness, length, bulk, and dirt content);7. over-all quality requirements; and8. price of the clothing. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 49
  50. 50. Prof.Dr. A.Kirecci - TE 211 Yarn Man. I 50

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